Organic light-emitting diodes (OLED) devices are widely used in mobile phone screens, computer monitors, and etc., because OLED has outstanding advantages of self-illumination, fast response, low driving voltage, high contrast, wide color gamut, and high luminous efficiency. Among them, flexible OLED display devices have become a main direction of research and development in the field of display technology in virtue of the bendable and portable properties.
At present, the most difficult problem that restricts the development of flexible OLED devices is that the lifetime of OLED devices is too short. The main reason is that materials of an electrode layer and a luminescent layer constituting the OLED device are quite sensitive to moisture and oxygen in the atmosphere, and performance of the device is weakened after subject to water and oxygen erosion. At present, a common TFE (Thin Film Encapsulation) encapsulation structure is a film structure of an inorganic material, an organic material and an inorganic material, and an EL (Electroluminescence) luminescent material is encapsulated inside the device, to achieve water blocking and oxygen blocking, and in turn provide protection for EL materials. It is extremely important to detect cracks of the encapsulation. It is beneficial to improve product quality and reduce cost if edge cracks of the encapsulation can be effectively detected before shipment. At present, the commonly used panel crack detection (PCD) method is to make a peripheral wiring at edges of the display device. When a crack occurs, the metal wiring will break, and a resistance at both ends is measured to determine whether a crack occurs.
In summary, the above PCD method of detecting the occurrence of cracks by detecting the resistance at both ends of the metal wiring can only detect whether the device has cracks, but it cannot accurately locate the crack.